بررسي نقش و رابطه بين عوامل ژيومرفولوژي ، خاك و پوشش گياهي در حوزه آبخيز بهشهر

Reviewing the rote and relation between xofl geomorphology and vegetation cover in behshahr water basin

Nowadays geomorphology studies are considered as the basis of the studies in natural resources. In this study characteristics of the natural environment of Miankaleh and Gorgan Gulf basins as well as basins of mountainous areas between Behshahr and Neka (Jahan Moureh Mountains) have been evaluated. In addition, the vegetation cover based on geomorphology and soil units have been examined The purpose of this study was realizing the precise relation and role of each of the environmental factors, such as soil, climate, and hydrologic status in providing vegetation cover of each geomorphological unit in the region. Therefore, environmental parameters were evaluated in each geomorphological unit based on a combination of Brown - Blanke and Kochler methods. In order to obtain basic maps, we used topographic maps (1:50000), aerial photos (1 : 20000), geology maps (1:250000), local visits, and morphologic maps. In addition, maps showing hydrography, lithology, height, slope and direction were used for this purpose. The obtained maps along with field visits were ased for providing the geomorphologic map in order to carry out geomorphology studies. As a result, two geological periods ( second and forth periods) with 4 types and 14 fades were identified in the area. In the climatology section, statistical data, obtained from meteorology stations in the area, as well as isohyets, isotherm and isovap maps were used and the climate of the region was specified through Ambrgeh and Do marten methods (1). In addition, physiographical studies and qualitative / quantitative hydrological reviews were carried out at this stage. For pedoligy purposes, profile digging and studying was carried out inside each geomorphological unit After sampling from different layers and analyzing the samples, the type of the soil was specified and new classifications were introduced. Then, according to Kovada Formula, the critical depth of the aquifer was determined. In order to determine plant communities and units in each geomorphologic unit, we carried out sampling and field cropping through florstic - physiognomic methods. Information such as the list of species, based on growth form, crown coverage and height were registered in florstic - physiognomic analysis list Through the above - mentioned informatioas, some 67 plant species in 31 plant units were identified. This study showed that the best methods for evaluating environmental variables in each plant community are those which choose geomorphologic units as the basis of the study. Therefore, the floristic - physiognomic method is introduced as the best method for identifying plant communities which reflect the current situation.